Object initialization in C# thread - unexplained behaviour

Hello all,

I have a C# class (in this example, called A) that, in its
constructor, starts a thread with a method of its own. That thread
will be used to continuously check for one of its object's state and
generate classe's A events "Connected" and "Disconnect ed".

It looks something like this:

"
public class A
{
private AnotherObject an_obj;
private Thread thr;
...

public event System.EventHan dler Connected;
public event System.EventHan dler Disconnected;

public A()
{
thr = new Thread(new ThreadStart(thi s.DoThreadWork) );
thr.Start();
while (!thr.IsAlive);
thr.IsBackgroun d = true;
}

private void DoThreadWork()
{
an_obj = new AnotherObject() ;

while(true)
{
if (an_obj.IsPrese nt())
if (Connected != null)
Connected(this, EventArgs.Empty );
else
if (Disconnected != null)
Disconnected(th is, EventArgs.Empty );
}
}

public void DoSomethingX()
{
an_obj.CallXWor k();
}

public int DoSomethingY()
{
return an_obj.CallYWor k();
}
}
"

and a form that uses the previous class:

"
public class Form1: System.Windows. Forms.Form
{
private A objA;
...

public Form1()
{
objA = new SmartcardEVCont roller();

objA.Connected += new EventHandler(ob jA_Connected);
objA.Disconnect ed += new EventHandler(ob jA_Disconnected );
}

private void objA_Connected( object sender, EventArgs e)
{
objA.DoSomethin gX();
}

private void objA_Disconnect ed(object sender, EventArgs e)
{
int i = objA.DoSomethin gY();
MessageBox.Show ("Value: " + i);
}

private void button1_Click(o bject sender, System.EventArg s e)
{
objA.DoSomethin gX();
MessageBox.Show ("Done");
}
}
"
The problem is that although every call made to object "objA", inside
the "objA_Connected " or "objA_Disconnec ted" captured event works
perfectly fine, when a method is called on "objA" anywhere else it
just blocks the program execution. In this example, when button1 is
clicked, the instruction "MessageBox.Sho w("Done");" won't get called
and the program (Form1) will stop responding.

By the way, class AnotherObj is a .NET wrapper for a C dll that, in
turn, is a JNI wrapper for a Java class. All Java methods are
"synchroniz ed".

I thought that this could be a problem of the Java object but the fact
is that the cycle inside the thread keeps on executing when calls are
made inside "objA_Connected " or "objA_Disconnec ted" and those calls
execute successfully, no matter how many calls are made to object
"objA".
A strange thing that happens is that the call "objA.DoSomethi ngX();"
inside the click event makes the corresponding Java method start
executing (using log utilities in Java, I can check that the method
began execution but then stopped for no apparent reason).

The only thing I can now think of is that the thread that is spawned
in the A class has some kind of own memory space that the object that
was initialized inside the thread ("an_obj") can't be safely used
outside the thread. Being the thread that generates the events
"Connected" and "Disconnect ed", that could explain that calls to
object "objA", inside "objA_Connected " and "objA_Disconnec ted",
executed well. But that's only an hipothetical thought.

p.s.: I also tried initializing object "an_obj" outside the thread, in
classe's A contructor, but that way the call "an_obj.IsPrese nt())"
would also block in the C dll (that calls JNI code) for no apparent
reason.

If anyone could give me an explanation of why this is happening and
what I can do to avoid it, I would be grateful, as I can't figure it
out just by myself.

Thank you very much,
Ricardo Pereira